Cheapest priced copy (Commander Legends): $0.99 at Card Kingdom, near mint, their price list as of .
Trench Behemoth 
Creature — Kraken · 7/7 · Rare · Commander Legends · #366
Return a land you control to its owner's hand: Untap this creature. It gains hexproof until end of turn.
Landfall — Whenever a land you control enters, target creature an opponent controls attacks during its controller's next combat phase if able.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Legends | 366 | Rare | $0.99 | — |
6 rulings from Wizards of the Coast
- 10 November 2020If the target creature does attack, its controller still chooses which player or planeswalker it attacks, as normal. It can attack opponents who don't control untapped Trench Behemoths waiting to crush it, if any are available.
- 10 November 2020You can activate Trench Behemoth's first ability even if it's already untapped and/or already has hexproof.
- 10 November 2020If the target creature can't attack for any reason (such as being tapped), then it doesn't attack. If there's a cost associated with having it attack, the player isn't forced to pay that cost, so it doesn't have to attack in that case either.
- 8 November 2024Whenever a land you control enters, each landfall ability of the permanents you control will trigger. You can put them on the stack in any order. The last ability you put on the stack will be the first one to resolve (As a result, you can have those abilities resolve in the order of your choosing.).
- 8 November 2024A landfall ability doesn't trigger if a permanent already on the battlefield becomes a land.
- 8 November 2024A landfall ability triggers whenever a land you control enters for any reason. It triggers whenever you play a land, as well as whenever a spell or ability puts a land onto the battlefield under your control.